In many industries, as for example in the mattress or bedding industry, it is common practice to secure two wires or rods, such as a spring element of a mattress to a border wire via clips made from sheet metal. Such clips are generally in a U-shape having an arcuate crown portion and oppositely spaced leg portions depending from the crown portion. The two wires to be interconnected are placed between the leg portions of the clip and the leg portions pushed together by a clinching tool, thus securing or locking the two wires together.
Such a clinching tool typically includes a generally J-shaped jaw into which the leading clip in a stack of clips is indexed. The clinching tool has a blade which shears off the first clip from a stack of clips placed inside the clinching tool. U.S. Pat. No. 2,574,811 shows such a clinching tool.
In order to operate the clinching tool it is necessary to place a plurality of clips inside the clinching tool in an orderly fashion. The clips must be similarly oriented and in an abutting relationship to one another, each clip abutting the two adjacent clips in an orderly fashion.
Clips must be interconnected to each other in a flexible manner so that the stack of clips can be wound into the clinching tool.
The clips must also be interconnected with sufficient strength so that they are able to withstand high tensile forces associated with winding and unwinding of the stack of clips upon a spool in the clinching machine. Accidental breakage of the connector connecting adjacent clips would be detrimental to the operation of the clinching machine.
One common way now used to interconnect similarly U-shaped clips together is by means of a non-metal, elongated flexible member such as rope or plastic. Slots or grooves through the arcuate portion of each U-shaped clip are lined up such that the non-metallic, elongated connecting piece of rope or plastic may be placed inside all of the grooves in order to connect the clips together in a flexible manner.
Several techniques have been developed to secure the rope or plastic connector inside the slots of each clip. One technique illustrated in U.S. Pat. No. 5,314,065 is to form the notches in the sides of the clips and to deform a portion of the clip so as to close these notches after insertion of the connector rope.
Another technique for fastening clips together has been by forming grooves or slots on the arcuate top portion of each U-shaped clip rather than on the lateral side edges. As shown in U.S. Pat. No. 5,303,821 these grooves are closed after the connecting rope or plastic is placed inside the grooves by deforming the side edges of the arcuate crown portion of each clip inwardly so as to crimp the plastic rope inside the grooves.
In all previously known U-shaped clips and method of interconnecting those clips a significant portion of each U-shaped clip must be cut away or removed in order to provide a groove or slot or notch for the reception of the connector. Removing such significant portions of the U-shaped clips weakens the strength of the clips, and wastes a substantial portion of the metal from which the clip is formed.
It has therefore been an objective of this invention to provide an improved clip and method of connecting clips into collated connected rows which is less wasteful of clip material.
It has been other objectives of the invention to provide an improved clip and method of collating and connecting clips into collated rows which results in improved clips of greater holding force with the same or less material used in the production of the clips.